The Lava Tunnel

September 13, 2025 -- A lava tunnel, or lava tube, is a natural underground cave formed by the flow of molten lava. Raufarholshellir is Iceland's fourth longest lava tunnel (4462 feet). It was formed by a volcanic eruption over 5,200 years ago. The tunnel was first explored in 1971 and has been open to tourists since 2017. It is a popular tourist attraction since it is not far from Reykjavik and can be accessed year-round. We went our second day in Iceland.

The volcanologist (our tour guide)

The tour

Our tour lasted about 60 minutes and cost about $60 a piece. It was worth it. Our tour guide was very good. She was a volcanologist. Never thought I'd use that word in a sentence. She was very knowledgeable, but also very entertaining. We had to wear hard hats. It was cold in the tunnel, increasing so, as you got towards the end of the tunnel. I'd never experience such darkness until all the lights were turned off, including our head lamps. It was truly pitch black.

Vivid colors

Different colors

Shadow puppet

There are over 500 lava tunnels in Iceland, though the exact number is unknown. According to our tour guide, sheep sometimes fall into lava tubes, leading to their discovery. A shepherd searching for the lost sheep might hear its bleating. Hopefully, he doesn't fall into the tube, too.  Lava tubes have been used for shelter, food and water sources, and ceremonial purposes. They are being considered as future habits on the moon and Mars. Who knew?

Lava's art

All smiles

In the tunnel without the lights on

Entrance to the lava tunnel